The self-assembly of europium oxide (Eu 2 O 3 ) nanocrystals into anisotropic one dimensional europium hydroxychloride (Eu(OH) 2 Cl) nanostructures is reported. Eu 2 O 3 nanocrystals, synthesized via colloidal chemistry, form one dimensional structures via a stepwise assembly and growth procedure. Transmission electron microscopy (HR-TEM) reveals the shape and crystal lattice spacing of the nanostructures, whereas X-ray diffraction (XRD) measurements characterize the nanocrystals' crystallinity. Photoluminescence measurements indicate changes in the site location and environment of the Eu 3+ ions.